The flight operation and control of an aircraft is dependent on the knowledge of the flight parameters of the latter, such as its speed relative to the ambient air, its altitude and angle-of-attack.
These parameters are determined by means of sensor probes located on the fuselage of the aircraft. In a known manner, these sensor probes include static pressure sensors, Pitot probes for measuring the total pressure, angle-of-attack probes mounted on a pneumatic device or a vane/paddle type device, and total temperature probes.
These probes are then connected to the means for determining the corresponding magnitude or quantity. In particular, an anemometer determines the speed of the aircraft relative to the air based on the measurements of total and static pressure, and an altimeter determines the altitude of the aircraft based on the measurements of static pressure.
These measurements are then pooled and displayed on a display device which constitutes a central information source based on which the flight operation and control of the aircraft is carried out.
In a known manner, the angle-of-attack probes and pressure probes are in the form of vanes and tubes protruding from the skin of the aircraft. They are thus exposed to meteorological or mechanical factors which can affect or alter the operation thereof, in particular by clogging the orifices of these probes with frost or dust or insects, or by blocking the vane devices.
Such failures lead to the generation of incorrect measurement readings, and in particular the display of false angles-of-attack, speeds and/or altitudes that may lead to the pilot performing inappropriate manoeuvres. For example, false flight control information can lead to the stalling of the aircraft or loss of control thereof on account of excessive speed.
In order to minimise the consequences of such malfunctions and failures, aviation regulations require aircraft manufacturers to provide for redundant means for measuring these critical features.
Thus, aircraft typically include at least one stand by sensor probe that is identical to each probe that may likely fail. However, this solution has not proven to be entirely satisfactory.
Indeed, the existing stand by sensor probes are for the most part of the protruding type and as a consequence present the same risks of malfunction or failure as the probes that they are intended to eventually replace.
Thus, in the event of the malfunction or failure of measurement probes, no reliable measurements are provided to the pilot.
Moreover, the pilot does not have any available means for verifying the reliability of the data and information provided by the sensor probes.